Use query string to track sources in forms
Recently I went down a hole trying to identify where people was coming from to submit forms and the biggest thread I was able to find was this one https://community.oracle.com/topliners/discussion/4351822/how-to-capture-referring-sources-to-landing-pages-and-in-forms-using-query-strings/p1 but even after all kind of changes and updates across all the comments, wasn't working for me.
1 - create your query string
2 - then go to assets / components / field merge
3 - create a new field merge and selecting "Query String" in the dropdown list
4 - type the name of your query string in the text box and save it